A correlative study of the function and pharmacology of froq retinal ganglion cells is proposed. Extracellular ganglion cell responses to a spatiotemporal white noise stimulus will be used to determine detailed receptive field properties. This technique provides an objective, quantitative basis for defining ganglion cell function. The analysis has been used extensively by the PI in frog and cat receptive field analysis. Traditional stimuli will continue to be used however in order that results can also be compared with previous work by other investigators. Using non-linear analysis, both spatial and temporal features of ganglion cell receptive fields will be determined. Picrotoxin and strychnine will be administered to the retina in order to block the Alpha-aminobutyric acid and glycine transmitters, respectively. These blockers will be given after a ganglion cell receptive field has been extensively classified. Electrophysiological procedures will then be repeated to test several hypotheses concerning the pharmacological basis underlying the ganglion cell's receptive field structure.